two color registration and files for plates

Registration for 2 colour, generally, & way back, in units with just a few Compositors, every Comp had their own, Pre-Make Ready Galley, simple as Pin Bar assembly at the head with clear acetate sheet’s available, first colour, laid down for position, into the grip on the machine, hand inked, with a *rubbing* taken on clear acetate sheet, located on the pin bar, second colour(s) laid down, positioned perfectly, under the acetate sheet, (to the same lay edge)
Even in the absence of unsophisticated/ancient technology it is not rocket science to insert 2/3 tiny pins into a regular length of furniture, 2/3/4/ ems wide and length to suit, with acetate sheet, D.I.Y. registration for a few cents.???

It sounds like the register is not really tight. You should be able to print the piece using regular gauge pins, just being extra careful to not move the pins between runs and to always feed the sheets with the same edges against the gauge pins. As far as preparing the plates digitally, if there are no overlaps between the two colors one way to do it is to make the image in one color, and send an accompanying file showing the color break so the plate maker can mask out the unwanted colors on the two plates. This used to be done by making the flat reflective art with a clear plastic overlay for the second color, with registration guides on both layers.

Bob

I have found the easiest way is to apply double-sided tape to the print-side of the second color plate. It’s best to put small pieces of the temporary double-sided tape (just enough to hold the plate, but not strongly) on the flat, non-raised areas of the second plate. Place a print of the first color run face-up on a flat surface. Turn the second color plate print side down onto the first color print, line up the registration marks and crop marks, if applicable, and press down on the double-sided tape on the plate. Remove the adhesive backing of the plate, register the first print stuck to the second color photopolymer plate with the registrations pins that should still be in your press and close the press by hand. The adhesive backing on the plate should overpower the double-sided tape and it’ll stick to the base right where it needs to be. I never would have thought of this until seeing it in a video by Boxcar Press. I unfortunately can no longer find the video.

Hope this helps!

Erica

If you’re planning on trimming down your work (instead of printing on the exact side of paper that you need), then you can set up registration marks on your photopolymer plate files. For me, when I do this, they usually double as crop marks, so I don’t include the circle in the middle. That way, they are trimmed away but are available for registration while on press.

I also use an acetate sheet over my tympan to print on and confirm my registration before I start printing the second color.

I really want to like the “tape down your plate onto the printed sheet” method with double-sided tape, but apparently I’m the only one who sometimes experiences a bit of wiggle that throws off my registration. It works sometimes, but not always.

How close are the colors? If they’re far enough apart to get scissors between, you don’t even need to have two plates made. Make the art in one color, have one plate made, and then cut them apart before mounting. If you make sure the cut is irregular, you can use the cut itself for registration purposes. Below is a link to a photo of the plates for a project I printed this way last year.

https://www.flickr.com/photos/mephit/9454243331/

Basically, you print one color, carefully place the second plate on the base aligned to the first, then peel the first plate off. Your plate and pins should be in perfect position for the second pass.

If the second color is too close for this technique to work you’ll need to have two plates made. What I do is add crop marks to the plate artwork for each color. I then take a straight-edge and sharp knife and cut the plate out from the crop marks, being careful to not cut all they way out of the plate. I wind up with a crop mark surround and a separate plate that match each other perfectly. If I cut every color out the same way, each set of crops matches each plate. I can then print the first color, carefully place a crop mark surround around the first plate, then peel the first plate off and carefully place the second plate inside the surround. Once I’ve got the second color placed, I peel off the crops. Again, the plate and pins should be perfectly placed for accurate register. Unfortunately, I don’t have a photo of this kind of thing right now, but I’ll try to get one taken in a couple of days.
—
Michael Hurley
Titivilus Press
Memphis, TN

@Hello Nifty

Yeah, I love when the double-sided tape method rips off my registration tabs. That’s always a blast. Definitely a less than perfect method.

I never thought to print on acetate first! Brilliant!

A little Addendum, (and with respect)! some of the above methods Hunky Dory for a one off, I.E. throw the first colour on, and then match it with no repeatable datum line to start with?? fine originally!! but how when A/The repeat comes in 2 days 2 weeks 2 months 2 years later = start again from scratch? not very scientific or forward thinking.
The method as described above, (pre-make ready galley) meant the acetate was either wiped clean Or left in the job bag, (dormant file) for future use, Surely even later day followers must keep file copies etc.
It was quite normal practice for repeat jobs @ a single page, or a 64 page job even, to go to another printer(s) with previous file copy, acetate sheet etc, so it could be duplicated perfectly colour for colour for register.???
8 x 8 pages per forme on a big press, although in competition, everybody worked to the *beat of the same drum* probably factored in by the customer.(s)
And it is a racing certainty that *Boxcar,s* base, hatched and lined for register, is not their own original, F.A.G., Cornerstone, etc etc had clear/acetate, pin bar graph sheets as early as the mid 50,s maybe earlier.!!
Spiel ends, with Apologies. but it was much less complicated and far more courteous, way Back, when.

Thanks everyone,

Super helpful! My question was answered. I am going to go with Michael on this one as my colors are touching and I will need to have two plates made. Seems foolproof form my first run.

*edited 7-22-14 as I noticed I’d forgotten my signature*

I’ve had a few moments to take and upload some photos of the method I use to register plates using a crops border. Note that in this case I was making sure the front and back of a card registered, not two colors on the same side, but the technique works for either.

The first photo shows the cut-off crops frame.
https://flic.kr/p/oqgQmH

Next is the first plate and how it fits into the frame.
https://flic.kr/p/ooeLtr

And finally, the second plate fitted into the same frame.
https://flic.kr/p/o72rnC

As you can see, both plates fit very tightly into the frame. This makes accurate color registration easier.
—
Michael Hurley
Titivilus Press
Memphis, TN

I am a rookie at this and used Michael’s cutting method above and it was easy and worked fine for the two color broadside I just printed.

I’m glad to hear it was useful to you! Which technique did you use, the one getting two colors out of a single plate or the method for registering two plates to each other? I can’t claim to have originated the former (I got it from a Boxcar Press video), but I did think up the second based on it (though I’m sure others have had the same thought before).
—
Michael Hurley
Titivilus Press
Memphis, TN